Step 1

Preheat the oven to 350 °F. Coat a 9×13-inch large casserole dish with nonstick spray and set aside.

Step 2

In a Dutch oven or deep skillet, heat 1 tablespoon olive oil over medium-high. Add 1 chopped onion and 2 chopped red bell peppers. Sauté for about 5 minutes until slightly softened.

Step 3

Add 1 pound ground beef, 2 tablespoons chili powder, 1 ½ teaspoons cumin, ½ teaspoon salt, ½ teaspoon ground black pepper, and ¼ teaspoon cayenne pepper. Sauté until the beef is cooked through, about 4 to 5 minutes. Add 2 minced garlic cloves and cook just until fragrant, about 1 minute.

Step 4

Remove the beef mixture from heat. Stir in 2 cups cooked brown rice and 1 cup plain Greek yogurt until evenly combined. Taste and adjust seasoning if needed.

Step 5

Spread 15 ounces refried black beans into an even layer in the prepared dish.

Step 6

Sprinkle ¼ cup grated Cheddar cheese and ¼ cup grated mozzarella cheese over the beans.

Step 7

Sprinkle the tomatoes and green chilies evenly over top.

Step 8

Spoon the ground beef mixture evenly on top of the tomatoes.

Step 9

Top with remaining ½ cup grated Cheddar and ½ cup grated mozzarella.

Step 10

Bake, uncovered, for about 15 minutes until the cheese is melted and the casserole is hot.

Step 11

Switch the oven to broil and continue cooking for 3-4 minutes until the cheese is lightly browned. Remove from the oven and let rest for 5 minutes.

Step 12

Sprinkle the Mexican casserole with chopped cilantro and green onions, and serve.